The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Hydraulic fracturing is a process of pumping liquids down a well and into a subterranean formation at high rate and pressure, such that a fracture is formed in the rock around the well. After pumping a liquid volume sufficient to widen the fracture adequately, solid particles, called “proppant,” are added to the liquid. After pumping is completed, the well is opened for production of hydrocarbons. The production rate and production service of fluid from the well is usually significantly increased after the fracturing treatment. Vast improvements in the hydraulic fracturing process have been developed since the process was originally patented in 1949. See US2013/0025862, the disclosure of which is included in its entirety herein, by reference.
The material first used for proppant in hydraulic fracturing of wells was silica sand. As wells became deeper, sand was sometimes found to have inadequate strength or other properties. In deep wells, stress of the earth can cause the sand to crush and become much less effective in increasing the production rate of a well.
Synthetic proppant materials were developed to provide higher strength proppants. One type of synthetic sintered proppant was sintered bauxite. In later years, a variety of ceramic raw materials have been used to make sintered ceramic proppants, including bauxite containing alumina and clay minerals, such as kaolin. However, there remains a continuing need to develop and supply synthetic proppants with select properties for placement in subterranean formation fractures with improved stress resistance and distribution, such need met at least in part, by the following disclosure.